The present invention relates to a method and apparatus for transillumination of various parts of a living body to avoid damaging such parts during an invasive procedure and more specifically to the use of two different light sources in such procedures.
Although the present invention is described in connection with protection of a ureter during a surgical procedure, this is done merely for purposes of ease of illustration; the invention being useful for protection of various body parts lying adjacent to a region subjected to an invasive procedure.
Currently practiced methods and devices used to transilluminate the ureters to permit ready location and thus protection of the ureter during endoscopic procedures require the cystoscopic placement of a catheter housing and a fiber optic light guide into the lumen of the ureter. The distal portion of the fiber optic light guide is treated to allow light preferably to emit circumferentially from the wall of the fiber. The proximal end of the fiber is coupled to a visible light source. A second light source is coupled to an endoscope and introduced into the surgical site.
Light detection of the transilluminated ureter using typical illuminating catheters such as the Bush DL(trademark) Ureteral Illuminating Catheter Set coupled to a light source during endoscopic procedure is facilitated with a camera. The camera projects the detected image of the transilluminated ureter on a monitor for visualization. Sufficient light from the predicate devices must traverse the ureter and overlying tissues with ample intensity to penetrate surrounding tissue and to overcome the illuminated field from the endoscopic light for the camera to detect light emanating from the transilluminated ureter. In the presence of the normally illuminated operative field from the endoscopic light, the camera frequently cannot detect light emanating from the transilluminated ureter. In an attempt to optimize and intraoperatively improve the performance of their device, Cook Urological, Inc., suggests that it may be necessary to dim or eliminate the endoscopic light illuminating the surgical field. The same problems are encountered in open field surgery where the overhead lights in the operating room may have as great an effect as the endoscopic light source.
It is an object of the present invention to permit ready detection of preferably both an infrared light source as well as a more standard light source as opposed to only an endoscopic light source during an invasive procedure in a region of a body adjacent the ureter or other body member to be protected.
It is another object of the present invention to provide a system and method permitting ease of discrimination of light energy emanating from a body member to be protected during an invasive procedure adjacent said body member from light introduced to illuminate the region of the procedure adjacent such body member.
It is yet another object of the present invention to protect a body member during a surgical procedure adjacent thereto by emitting modulated electromagnetic radiation from such member to permit ready detection of such radiation in the presence of visible light illuminating the area of the procedure.
Still another object of the present invention is to transmit infrared light through a body part to be protected during a surgical procedure and to maintain the surgical site otherwise free of infrared energy by filtering out infrared energy from an endoscopic or other light source if such is employed.
Yet another object of the present invention is to transmit continuously electromagnetic energy through a body member to be protected during an invasive procedure in a region adjacent thereto and to pulse a light employed to illuminate the region during the procedure.
Another object of the present invention is to synchronize emissions of electromagnetic energy from a body to be protected during a surgical procedure in a region adjacent thereto with emission of light into the region for illumination thereof.
Still another object of the present invention is to synchronize a camera shutter with periodic emission of light into a region being subjected to an invasive procedure with periodic emission of detectable energy from a body member to be protected from injury during such invasive procedure.
Yet another object of the present invention is to couple an optical fiber employed to detect light emitted by a source located in a body part to be protected, to a surgical instrument to be inserted into a body cavity in which a procedure is to be conducted.
It is still another object of the present invention to transmit infrared energy through a body member to be protected during surgery into a region illuminated by an endoscopic light source from which infrared energy has essentially been removed.
Another object of the present invention is to employ an infrared energy source to illuminate a region of a body and view the region with a camera sensitive to both visible and infrared light energy.
Yet another object of the present invention is to transilluminate a body member or region with infrared energy to enhance the view of the region whereby to facilitate a surgical procedure.
Still another object of the present invention is to transmit infrared light energy down a nerve to be protected during a surgical procedure to cause the nerve to become an infrared light energy transmitter.
The use of infrared emission detection is central to the technology of the present invention.
In particular, the technology takes advantage of the inherent transmissivity of infrared through biological tissues in the range from 700 nm to 1,300 nm. Optically, all biological tissues are considered composite structures consisting of a scattering medium imbibed with various molecular components that absorb light at specific wavelengths. The amount of light absorbed by different molecules is dependent on the chemical and physical properties of the molecule. In the visible part of the spectrum (400 to 650 nm), intense absorption due to hemoglobin and light loss caused by scattering prevents transmission of visible light over more than a few millimeters of tissue. In the infrared spectrum above 1,300 nm, water present in tissue acts as an effective absorber of infrared at this wavelength, again limiting the transmission of infrared longer than 1,300 nm to a short distance. In the infrared range of 700 to 1,300 nm, however, a significant amount of infrared light can be transmitted through several centimeters of biological tissue. This window of high transmissivity is due to the lack of lack of molecular components that absorb infrared between 700 nm and 1,300 nm.
The present invention makes use of the fact that infrared energy can be transmitted through several centimeters of biological tissues to implement various procedures such as protection of organs, etc., during invasive procedures adjacent an organ, to transilluminate an organ to locate it and view it and to render nerves visible over a length thereof.
In a first embodiment of the invention a probe is employed to detect infrared energy during a laparoscopic operation. An endoscopic light source is pulsed while continuous emissions of infrared energy are provided from within a body member to be protected, such as a ureter, duct, colon, blood vessel or other body member. The visible and infrared light energies are directed by the probe to a video camera and then to a monitor. The endoscopic light source is pulsed on at every other frame or half frame of an interlaced display on the monitor so that every other full frame or half frame displays both the member to be protected and the area of the operation and the next frame or half of the interlaced frame displays only the emission from within the body member to be protected. Thus, the body member emission is enhanced.
In a second embodiment of the invention an infrared light energy source is disposed in a body member to be protected during surgery or other invasive procedure in the region of said body member and is pulsed on when visible light from the endoscopic light source is projected into such region is off and vice versa. The on-time of the source in the body member is synchronized with operation of the shutter of a video camera employed to protect an image of a body member on a monitor. In this arrangement, the body member and the region of the invasion of the body are displayed in alternate frames on the monitor. As will become apparent below, elimination of infrared energy from the endoscopic light source further enhances visualization of the member to be protected.
In the event the procedure involved is an open body procedure and the visible light source is the standard overhead array of lights in an operating room, the visible lights cannot be pulsed and therefore only the infrared source is pulsed. The detectors then must be sensitive only to infrared and/or to a 12 KHz signal imposed on the infrared light.
In another embodiment of the invention, the light fiber employed to detect light transmitted through a body member in the surgical area is secured to a surgical instrument to be inserted into and used in such area. The fiber may be carried by a sleeve slipped over the instrument which may be a scissor, a stapler, or the like. The fiber may be mounted so as to be forward looking. Alternatively, single or multiple fibers may be mounted so as to be side looking or forward and side looking as determined by the requirements of the surgical site and instrument.
In still another embodiment of the invention, an audible alarm is used in the former two embodiments of the invention and is synchronized with the infrared light source. Thus, such alarm does not respond to infrared energy of the endoscopic light source and the level of infrared energy to produce detection may as a result be reduced to provide information at an even greater distance from the member to be protected than might otherwise be the case. The alarm may be of constant amplitude or may vary as a function of the distance of the probe from the infrared emitter.
In a further preferred embodiment of the invention, infrared light energy is transmitted through a body part to be protected during laparoscopic procedures while the rest of the surgical site is infrared free, this being accomplished by removing infrared energy from the light emitted by the endoscopic light source employed to illuminate the surgical site. This effect is achieved by employing an infrared blocking filter between the endoscopic light source and the surgical site. In this embodiment, and useful in the other embodiments, the endoscope has an annulus of optic fibers for conducting light from an endoscopic light source to the surgical site and a centrally located lens for transmitting light from the surgical site to a CCD of a video camera, the lens having a focal length to accommodate the length of the endoscope.
In such embodiment of the invention the infrared blocking filter may be inserted into the light path from the endoscopic light source whereby infrared light energy from an emitter in or adjacent to an organ or the like to be protected will be the only substantial source of infrared energy in the operative region. Thus, response of the alarm will be limited to infrared energy from the body to be protected. Further, the video camera is made sensitive to both visual and infrared energy so the infrared energy source will be clearly identified.
The present invention also discloses the use of transillumination of a region subject to a surgical procedure. In one such illustrative application an infrared energy source is inserted into the region of the knee joint and an infrared energy probe connected to a video camera and monitor is either inserted into the opposite side of the joint or placed on the surface of the skin on the oppose side of the joint. Because the articular cartilage and surrounding tissues are generally white and translucent with not great color contrast, the transillumination yields improved overall illumination of the surgical site while improving definition of the structures lying between the source and the probe.
In a laparoscopic procedure, the location of an infrared energy source used to transilluminate internal organs, tissues, bones, etc., may be detected by an infrared detector probe and positioning is rendered less difficult. An endoscopic source and detector probe may then be accurately positioned in the operative region for detection of the region to be treated.
In the protection of nerves, it has been found that when an infrared energy emitter is placed in contact with a nerve, the infrared energy is transmitted along the nerve, which then becomes an infrared energy emitter along a length thereof, thus identifying the location of such length. The length of the nerve that is thus identified depends upon the energy of the infrared energy source.
The infrared energy source in the original system of the present invention was a 5 milliwatt source. The system has been configured to utilize a 1 watt source and in fact uses two such sources. In tests conducted to date only 256 mW have been used. The second source is used to transilluminate an organ such as the bladder while an infrared emitter is inserted for instance in the ureter. The transillumination may assist in locating various members at the actual surgical site. Thus, blood vessels, ligaments, ducts, stones in various organs, all or any one of which may be involved in the surgical procedure can be located while at the same time the ureter, etc., are protected utilizing the other laser source.
In all of the above embodiments a polarizing filter may be placed in the light path to the camera to reduce glare.
All of the above systems may be operated with NTSC, PAL or SECAM video systems so that, as appropriate, frames may be interlaced as indicated hereinafter, if so desired.
The above and other features, objects and advantages of the present invention, together with the best means contemplated by the inventor thereof for carrying out the invention, will become more apparent from reading the following description of a preferred embodiment and perusing the associated drawings in which: